This invention relates to a display device, and more particularly to a display device which visually indicates the abnormal condition of an apparatus, for example, an electronic copying machine, and the countermeasures therefor.
To date, there has already been commercially manufactured a device for displaying the number of sheets in which an impression has already been copied and another device which visually informs the operator of the condition in which some section of the copying machine is jammed with copying sheets. Pictorial patterns or notations representing those conditions of a copying machine which have to be detected are impressed on the transparent display panel of the display device. Some detected condition of a copying machine is displayed by illuminating the corresponding pictorial pattern or notation by a lamp provided at the back of the display panel. The operator takes proper countermeasures by looking at one displayed condition. Said countermeasures can be easily taken by a well-skilled copying machine operator. However, novice operators of said copying machine or those unaccustomed to its operation find difficulties in taking proper countermeasures. Therefore, the novice operator will have to be informed of countermeasures for the current condition of a copying machine by looking at an accompanying explanatory note. If the explanatory note is not easily available, the operator will have to ask for the advice from a skilled copying machine operator on the countermeasures to be taken. If the novice operator tries to take countermeasures only from his own doubtful knowledge, then the copying machine will probably be damaged.